Report from working group Nordic-Nat
Summary
The aim of this document has been to make an overview of radon management and have a closer look at the similarities and differences between the Nordic countries in this matter. The document is not exhaustive but will be useful for the Nordic co-operation and serves as a basis for further discussions and work to achieve our goals given in the mandate of the Nordic-Nat group.
When comparing typical radon activity concentrations e.g. in dwellings, drinking water, etc. it can be seen that the challenges are relatively similar in Finland, Norway and Sweden. Denmark has a less widespread problem, and the radon activity concentrations are generally lower, but the problem is definitely present. In Iceland several national surveys have shown that the radon activity concentrations both in indoor air and drinking water are overall very low.
However, comparisons between surveys or individually measured buildings in the different countries must be made with caution. That is one of the reasons that this document will be very useful. For instance, this study has shown that the measurement procedures vary between the Nordic countries. One example is that the seasonal correction factor varies between 0.75 and 1 (no correction). Further, the reference level in Denmark and Sweden refers to an average of measurements in the dwelling, while in Norway it refers to each single living- and bedroom. In Finland, the radon activity concentration in dwellings was reported as the average of the measurement results according to the housing health guidelines until 2016. At that time, the application guide for housing health legislation was updated, in which radon was no longer mentioned. In practice, the outdated guideline has still been in use.
The reference level for existing dwellings and premises where the public have access varies between 100 and 300 Bq/m3 and limit/reference values in new buildings between 100 and 200 Bq/m3 . Norway differs from the other countries in having a two-part system of reference values.
Further, there are differences between the countries in how long the limit/reference values given in the national building regulations for a new building apply. In Denmark it applies as long as the building exists, and consequently all buildings constructed according to the provisions in Building Regulations 2010 or later are subject to the limit value of 100 Bq/m3. In Finland, the reference value for new buildings is usually valid for 10 years after completion. In Norway the regulations apply until the certificate of completion is issued, but with a general warranty period of 5 years. In Sweden, the requirement must be met in such a way that with normal maintenance the requirement can be assumed to continue to be met for an economically reasonable lifetime of the building, in accordance with 8 chapter, 5 section 2 item in the Planning and Building Act (SFS, 2010:900). Should the requirement become stricter in the future for new buildings, you cannot be obliged to upgrade the building.
In addition to the limit value, solutions for preventive measures in new buildings are mandatory and specifically mentioned in the regulation in Norway. In Denmark, Finland and Sweden, the limit/reference values are given in the regulations, and guidance material is provided on how to fulfil the regulatory limit values by means of preventive measures.
In Sweden, the national grants for radon remediation in dwellings that were offered by the authorities in two periodes, 1988-2015 and 2018-2021 have been discontinued. The general tax deduction for craftsman services in private dwellings still exists. Similar general tax deductions are offered in Finland. In Denmark the tax deduction option for costs related to radon mitigation measures in existing dwellings, was abolished in April 2022. In Norway no grants or tax deductions are offered.
Denmark, Finland and Sweden all have reference levels and/or limit values for workplaces stated in national regulations. In Norway the workplace is regulated in general terms in the regulations and reference values are given in guidance material.
When it comes to drinking water the recommendations and requirements also differ between the countries. For waterworks the quality requirements of radon activity concentration are either 100 or 1000 Bq/L. The countries with the highest quality requirements levels have a quality target value of 100 or 300 Bq/L. For private wells there are no requirements, but the quality recommendations vary between 500 and 1000 Bq/L.
Finland, Denmark and Sweden have implemented reference levels for doses caused by gamma radiation in new buildings and building materials in the national regulations. In Norway gamma radiation in buildings and building material is not regulated.